The pattern of covalent histone modifications throughout the β-globin gene locus in fetal liver and adult bone marrow erythroblasts pre- and post-decitabine

2007 ◽  
Vol 38 (2) ◽  
pp. 151
Author(s):  
Donald Lavelle ◽  
Janet Chin ◽  
Kestis Vaitkus ◽  
Mahipal Singh ◽  
Maria Hankewych ◽  
...  
1986 ◽  
Vol 6 (4) ◽  
pp. 1108-1116 ◽  
Author(s):  
M Yagi ◽  
R Gelinas ◽  
J T Elder ◽  
M Peretz ◽  
T Papayannopoulou ◽  
...  

The human alpha-like globins undergo a switch from the embryonic zeta-chain to the alpha-chain early in human development, at approximately the same time as the beta-like globins switch from the embryonic epsilon-to the fetal gamma-chains. We investigated the chromatin structure of the human alpha-globin gene cluster in fetal and adult erythroid cells. Our results indicate that DNase I-hypersensitive sites exist at the 5' ends of the alpha 1- and alpha 2-globin genes as well as at several other sites in the cluster in all erythroid cells examined. In addition, early and late fetal liver erythroid cells and adult bone marrow cells contain hypersensitive sites at the 5' end of the zeta gene, and in a purified population of 130-day-old fetal erythroid cells, the entire zeta-to alpha-globin region is sensitive to DNase I digestion. The presence of features of active chromatin in the zeta-globin region in fetal liver and adult bone marrow cells led us to investigate the transcription of zeta in these cells. By nuclear runoff transcription studies, we showed that initiated polymerases are present on the zeta-globin gene in these normal erythroid cells. Immunofluorescence with anti-zeta-globin antibodies also showed that late fetal liver cells contain zeta-globin. These findings demonstrate that expression of the embryonic zeta-globin continues at a low level in normal cells beyond the embryonic to fetal globin switch.


Blood ◽  
1987 ◽  
Vol 69 (6) ◽  
pp. 1674-1681 ◽  
Author(s):  
BA Miller ◽  
SP Perrine ◽  
G Antognetti ◽  
DH Perlmutter ◽  
SG Emerson ◽  
...  

Abstract Interferons have the ability to enhance or diminish the expression of specific genes and have been shown to affect the proliferation of certain cells. Here, the effect of gamma-interferon on fetal hemoglobin synthesis by purified cord blood, fetal liver, and adult bone marrow erythroid progenitors was studied with a radioligand assay to measure hemoglobin production by BFU-E-derived erythroblasts. Coculture with recombinant gamma-interferon resulted in a significant and dose- dependent decrease in fetal hemoglobin production by neonatal and adult, but not fetal, BFU-E-derived erythroblasts. Accumulation of fetal hemoglobin by cord blood BFU-E-derived erythroblasts decreased up to 38.1% of control cultures (erythropoietin only). Synthesis of both G gamma/A gamma globin was decreased, since the G gamma/A gamma ratio was unchanged. Picograms fetal hemoglobin per cell was decreased by gamma- interferon addition, but picograms total hemoglobin was unchanged, demonstrating that a reciprocal increase in beta-globin production occurred in cultures treated with gamma-interferon. No toxic effect of gamma-interferon on colony growth was noted. The addition of gamma- interferon to cultures resulted in a decrease in the percentage of HbF produced by adult BFU-E-derived cells to 45.6% of control. Fetal hemoglobin production by cord blood, fetal liver, and adult bone marrow erythroid progenitors, was not significantly affected by the addition of recombinant GM-CSF, recombinant interleukin 1 (IL-1), recombinant IL- 2, or recombinant alpha-interferon. Although fetal progenitor cells appear unable to alter their fetal hemoglobin program in response to any of the growth factors added here, the interaction of neonatal and adult erythroid progenitors with gamma-interferon results in an altered expression of globin genes. This supports the concept that developmental globin gene switching can be regulated by environmental factors.


1986 ◽  
Vol 6 (4) ◽  
pp. 1108-1116
Author(s):  
M Yagi ◽  
R Gelinas ◽  
J T Elder ◽  
M Peretz ◽  
T Papayannopoulou ◽  
...  

The human alpha-like globins undergo a switch from the embryonic zeta-chain to the alpha-chain early in human development, at approximately the same time as the beta-like globins switch from the embryonic epsilon-to the fetal gamma-chains. We investigated the chromatin structure of the human alpha-globin gene cluster in fetal and adult erythroid cells. Our results indicate that DNase I-hypersensitive sites exist at the 5' ends of the alpha 1- and alpha 2-globin genes as well as at several other sites in the cluster in all erythroid cells examined. In addition, early and late fetal liver erythroid cells and adult bone marrow cells contain hypersensitive sites at the 5' end of the zeta gene, and in a purified population of 130-day-old fetal erythroid cells, the entire zeta-to alpha-globin region is sensitive to DNase I digestion. The presence of features of active chromatin in the zeta-globin region in fetal liver and adult bone marrow cells led us to investigate the transcription of zeta in these cells. By nuclear runoff transcription studies, we showed that initiated polymerases are present on the zeta-globin gene in these normal erythroid cells. Immunofluorescence with anti-zeta-globin antibodies also showed that late fetal liver cells contain zeta-globin. These findings demonstrate that expression of the embryonic zeta-globin continues at a low level in normal cells beyond the embryonic to fetal globin switch.


Blood ◽  
2006 ◽  
Vol 108 (11) ◽  
pp. 556-556
Author(s):  
Mahipal Singh ◽  
Kestas Vaitkus ◽  
Donald Lavelle ◽  
Maria Hankeywich ◽  
Nadim Mahmud ◽  
...  

Abstract The DNA demethylating drug (5–Az–2′–deoxycytidine) elevates fetal hemoglobin (HbF) to therapeutic levels in patients with sickle cell disease. To further investigate the mechanism of action of this drug and the role of DNA methylation in γ–globin gene silencing, we have analyzed the level of methylation of five CpG sites in the 5′ region of the γ–globin gene in highly purified subpopulations of cells representing different stages of erythroid differentiation from baboon (P. Anubis) using bisulfite sequencing. Baboons were treated with three different doses of decitabine (0.52, 0.26, 0.17mg/kg/day) for 10 consecutive days and pre-treatment and post-treatment adult bone marrow (ABM) were analyzed. Fetal liver (FL;n=2) and ABM cells were purified by depletion of the erythroblast subpopulation using an anti-RBC antibody (Pharmingen) in combination with immunomagnetic columns (Miltenyi) and FACS purification of CD34+CD36−, CD34+CD36+ and CD34− CD36+ subpopulations. Clonal analysis of sorted subpopulations demonstrated enrichment of CFUe in the CD34−CD36+ subpopulation, BFUe in the CD34+CD36+ subpopulation and both BFUe and CFU-GM in the CD34+CD36− subpopulation, thus confirming that these sorted subpopulations were enriched for the cells representing different stages of erythroid differentiation. A progressive decrease in the level of γ-globin gene methylation, as the degree of differentiation increased, was observed in the subpopulations purified from FL (Table 1). In pre-treatment ABM the level of γ-globin gene methylation was significantly (P<0.05) reduced in erythroblasts when compared to the CD34+CD36− subpopulation. Decitabine treatment reduced the level of γ-globin gene methylation in a dose dependant manner to a similar extent in each subpopulation except the CD34+CD36− subpopulation that exhibited only minor reduction in the γ-globin gene methylation. These results demonstrate that decitabine treatment demethylates the γ-globin gene primarily in late erythroid progenitors (CD34+CD36+) and erythroid precursors (CD34−CD36+). Methylation of the γ-globin gene is not significantly reduced in the more primitive CD34+CD36- subpopulation after decitabine treatment. The greater sensitivity of the progenitor/precursor subpopulations may be due to increased cell cycle kinetics. The increased levels of DNA methytransferase in CD34+ cells may also contribute to the relative insensitivity of the most primitive subpopulation to decitabine. This analysis identifies the late progenitor/precursor subpopulation as the target subpopulation most sensitive to DNA demethylation by decitabine while the early progenitor/stem cell subpopulation is insensitive to the drug. Table 1: DNA methylation (%) of the γ-globin gene in purified cells of fetal liver and pre- and post-decitabine treated adult bone marrow samples Samples CD34+CD36− CD34+CD36+ CD34−CD36+ Erythroblasts Note: Decitabine doses for PA6973=0.52mg; PA6974=0.26mg; PA7002=0.17mg/kg/day Fetal liver (n=2) 95.4±3.96 66.25±4.17 27.3±1.41 3.7±5.23 ABM-pretreated (n=3) 96.23±0.48 87.21±5.96 79.59±13.42 74.87±8.87 BM-post treated PA6973 85.40 41.30 31.10 37.80 BM-post treated PA6974 94.83 61.90 50.79 52.46 BM-post treated PA7002 92.31 71.93 66.00 58.00


Blood ◽  
1987 ◽  
Vol 69 (6) ◽  
pp. 1674-1681
Author(s):  
BA Miller ◽  
SP Perrine ◽  
G Antognetti ◽  
DH Perlmutter ◽  
SG Emerson ◽  
...  

Interferons have the ability to enhance or diminish the expression of specific genes and have been shown to affect the proliferation of certain cells. Here, the effect of gamma-interferon on fetal hemoglobin synthesis by purified cord blood, fetal liver, and adult bone marrow erythroid progenitors was studied with a radioligand assay to measure hemoglobin production by BFU-E-derived erythroblasts. Coculture with recombinant gamma-interferon resulted in a significant and dose- dependent decrease in fetal hemoglobin production by neonatal and adult, but not fetal, BFU-E-derived erythroblasts. Accumulation of fetal hemoglobin by cord blood BFU-E-derived erythroblasts decreased up to 38.1% of control cultures (erythropoietin only). Synthesis of both G gamma/A gamma globin was decreased, since the G gamma/A gamma ratio was unchanged. Picograms fetal hemoglobin per cell was decreased by gamma- interferon addition, but picograms total hemoglobin was unchanged, demonstrating that a reciprocal increase in beta-globin production occurred in cultures treated with gamma-interferon. No toxic effect of gamma-interferon on colony growth was noted. The addition of gamma- interferon to cultures resulted in a decrease in the percentage of HbF produced by adult BFU-E-derived cells to 45.6% of control. Fetal hemoglobin production by cord blood, fetal liver, and adult bone marrow erythroid progenitors, was not significantly affected by the addition of recombinant GM-CSF, recombinant interleukin 1 (IL-1), recombinant IL- 2, or recombinant alpha-interferon. Although fetal progenitor cells appear unable to alter their fetal hemoglobin program in response to any of the growth factors added here, the interaction of neonatal and adult erythroid progenitors with gamma-interferon results in an altered expression of globin genes. This supports the concept that developmental globin gene switching can be regulated by environmental factors.


2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Yi Yu ◽  
Alejandra Vargas Valderrama ◽  
Zhongchao Han ◽  
Georges Uzan ◽  
Sina Naserian ◽  
...  

Abstract Background Mesenchymal stem cells (MSCs) exhibit active abilities to suppress or modulate deleterious immune responses by various molecular mechanisms. These cells are the subject of major translational efforts as cellular therapies for immune-related diseases and transplantations. Plenty of preclinical studies and clinical trials employing MSCs have shown promising safety and efficacy outcomes and also shed light on the modifications in the frequency and function of regulatory T cells (T regs). Nevertheless, the mechanisms underlying these observations are not well known. Direct cell contact, soluble factor production, and turning antigen-presenting cells into tolerogenic phenotypes, have been proposed to be among possible mechanisms by which MSCs produce an immunomodulatory environment for T reg expansion and activity. We and others demonstrated that adult bone marrow (BM)-MSCs suppress adaptive immune responses directly by inhibiting the proliferation of CD4+ helper and CD8+ cytotoxic T cells but also indirectly through the induction of T regs. In parallel, we demonstrated that fetal liver (FL)-MSCs demonstrates much longer-lasting immunomodulatory properties compared to BM-MSCs, by inhibiting directly the proliferation and activation of CD4+ and CD8+ T cells. Therefore, we investigated if FL-MSCs exert their strong immunosuppressive effect also indirectly through induction of T regs. Methods MSCs were obtained from FL and adult BM and characterized according to their surface antigen expression, their multilineage differentiation, and their proliferation potential. Using different in vitro combinations, we performed co-cultures of FL- or BM-MSCs and murine CD3+CD25−T cells to investigate immunosuppressive effects of MSCs on T cells and to quantify their capacity to induce functional T regs. Results We demonstrated that although both types of MSC display similar cell surface phenotypic profile and differentiation capacity, FL-MSCs have significantly higher proliferative capacity and ability to suppress both CD4+ and CD8+ murine T cell proliferation and to modulate them towards less active phenotypes than adult BM-MSCs. Moreover, their substantial suppressive effect was associated with an outstanding increase of functional CD4+CD25+Foxp3+ T regs compared to BM-MSCs. Conclusions These results highlight the immunosuppressive activity of FL-MSCs on T cells and show for the first time that one of the main immunoregulatory mechanisms of FL-MSCs passes through active and functional T reg induction.


1997 ◽  
Vol 177 (1) ◽  
pp. 18-25 ◽  
Author(s):  
Yoshihiro Watanabe ◽  
Yuichi Aiba ◽  
Yoshimoto Katsura

Blood ◽  
2015 ◽  
Vol 126 (23) ◽  
pp. 3637-3637
Author(s):  
Vincenzo Giambra ◽  
Sonya H Lam ◽  
Miriam Belmonte ◽  
Sam Gusscott ◽  
Sohrab Salehi ◽  
...  

Abstract T-cell acute lymphoblastic leukemia (T-ALL) is a malignancy of immature T-cell progenitors, characterized by activating NOTCH1 mutations in over 50% of children and adult cases. Although intensive multiagent chemotherapy achieves cure in most pediatric patients, the majority of adults succumb quickly to their disease. The basis for this divergence is likely multifactorial, but we sought in this study to investigate whether cell intrinsic features might contribute to the disparate biologies in pediatric and adult patients. In our prior abstract, we modeled pediatric and adult leukemias by transduction of hematopoietic stem/progenitor cells (HSPC) derived from mouse fetal liver (FL) and adult bone marrow (ABM) with activated NOTCH1 virus followed by transplantation into histocompatible recipient animals. We observed that whereas FL- and ABM-derived HSPC generate similar primary acute T-cell leukemias in terms of penetrance, latency, disease burden/distribution, and immunophenotype, FL leukemias exhibit much greater cycling activity than ABM leukemias, yet are dramatically impaired in their ability to propagate disease in secondary and tertiary recipients compared to ABM leukemias. Using a combination of gene expression profiling and in vitro culture assays, we attributed this differential behavior to NOTCH1-induced autocrine IGF signaling that is operative in FL, but not ABM-derived HSPC. Here we report that NOTCH1 mediates its effects on IGF1 in FL-derived HSPC directly by physical occupancy over the IGF1 promoter in a dimerization-dependent fashion. As well, increased NOTCH1 occupancy at the IGF1 promoter region in FL tissues is associated with reduced histone H3K27 trimethylation (a mark of transcriptionally silent chromatin), yet there is equivalent histone H3K4 trimethylation (a mark identifying transcriptionally active promoters) in both FL and ABM tissues, suggesting that NOTCH1 may be responsible for interconverting the IGF1 locus between active and inactive, but poised chromatin states. NOTCH1 occupancy is also associated with enhanced physical interactions between the IGF1 promoter region and distant genomic loci as revealed by circularized chromosome conformation capture (4C) assay and confirmed by chromosome conformation capture (3C) assay, including sites with H3K4 monomethylation (a mark of transcriptional enhancers) suggesting that NOTCH1 promotes "looping in" of distant enhancer elements that drive IGF1 expression in FL tissues. We conclude from these studies that NOTCH1 enacts differential, developmental stage-specific transcriptional programs by a combination of local epigenetic patterning and long-range genomic interactions. These findings support the notion that pediatric and adult T-ALL may potentially be regarded as related, but biologically distinct diseases, and that novel, age-specific therapies that exploit these differences may improve clinical outcomes. Disclosures No relevant conflicts of interest to declare.


Sign in / Sign up

Export Citation Format

Share Document